Philip Bensing, a neighbor in American Canyon of the dead woman, Nellie Turner Stanworth, says her son told him she died about a month ago and been given a "military burial."

Photo: Sean Havey, The Chronicle

Philip Bensing, a neighbor in American Canyon of the dead woman,...

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Dennis Stanworth.

Photo: Vallejo Police Department

Dennis Stanworth.

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American Canyon resident, Philip Bensing, stands outside his mobile home where his elderly neighbor was allegedly murdered by her son, Dennis Stanworth, on January 10, 2013 in American Canyon, Calif. Dennis Stanworth was convicted in the 1960's of raping and murdering two teenage girls and was sentenced to death but eventually won parole.

More than 45 years ago, Dennis Stanworth would have been happy to die for murdering two teenage girls from Contra Costa County, telling the state's highest court to "give me an endless sleep as soon as you can."

Stanworth never was executed for his crimes, however, and through legal twists and turns eventually made it not only off Death Row but out of prison. Now, after more than two decades during which he stayed out of trouble, Stanworth is back in jail after allegedly admitting to Vallejo police that he killed his 90-year-old mother.

Stanworth, 70, called police at 11:55 a.m. Wednesday and said he had killed his mother at his home on the 2500 block of Marshfield Road, said police Lt. Jim O'Connell.

When officers arrived, Stanworth directed them to an area where they found the body of Nellie Turner Stanworth, O'Connell said. Police did not say how she was killed and weren't sure of a motive.

Philip Bensing, 78, a neighbor of the victim in a mobile-home park in American Canyon, said Dennis Stanworth told him about a month ago that she had died and been given a "military burial."

"He went like this," Bensing said, giving a thumbs-down sign, "and said she passed away a week earlier."

Moved her out

That was a few months after Stanworth had moved his mother into an assisted-living center, Bensing said. She later moved in with a relative, Stanworth told Bensing.

Bensing said Stanworth had continued picking up his mother's mail at the mobile-home park, in a car sporting stickers espousing support for police groups. A real-estate sign sat outside her home Thursday.

Now Stanworth is behind bars, just as he was for nearly a quarter of a century after he committed a string of rapes and a notorious double murder.

Stanworth was sentenced to death in 1966 for kidnapping and shooting to death two girls, ages 14 and 15. Five years later, the California Supreme Court overturned his death sentence because of irregularities during jury selection.

Life in prison

Stanworth was again sentenced to death after a retrial, but that term was commuted to life in prison in 1974 after the state's capital punishment law was declared unconstitutional.

He was paroled in 1990, and for the past decade has lived in a three-bedroom home in Vallejo's Hiddenbrooke neighborhood with his wife and father-in-law. The only mark on his record in recent years appears to be a seat-belt violation in 2011.

Irving Vanderberg, who lives across the street, said he had seen Stanworth working out at a local gym and that he "was friendly to me. He didn't seem to be a mean person."

But his horrific past wasn't a secret in the quiet neighborhood.

"Everybody in the neighborhood knew" that he had killed the two girls, said Vanderberg's wife, Carole Vanderberg.

"There were a lot of tears and worry," said Anne Connors, 38, who found out about Stanworth after she moved to the street with her four children in 2010. "But I didn't want to live in fear and not let my kids walk the dog. I didn't let them out of my sight."

Girls were hitchhiking

Stanworth was 24 years old on Aug. 1, 1966, when he picked up Susan Box, 15, and Caree Collison, 14, both students at De Anza High School in El Sobrante, as they were hitchhiking in Pinole. He drove them to a spot overlooking San Pablo Bay, where he forced them at gunpoint to disrobe and shot Collison in the head when she tried to escape. Then he shot Box and had sex with her body, according to court records.

As he left the scene, he heard "one of the girls moan," court records said, so he fired more shots at them.

Before the killings, Stanworth kidnapped three young women in El Sobrante and Richmond in separate incidents in 1965 and 1966 and sexually assaulted them, court records show. He choked one of the women into unconsciousness, then told her when she awoke that "he was glad he had not killed her, that he was sorry for what had happened and that he would not do it again," according to court records.

Stanworth, who was an unemployed house painter with a wife and two children, pleaded guilty to murder and other charges, testifying that he "couldn't live with it anymore. ... I just had to tell somebody."

Plea to high court

Stanworth later wrote to the California Supreme Court that he wanted to waive the automatic appeal of his death sentence because "it would save me many months of useless existence here on Death Row."

He added that he had "dishonored my family's name, not to mention the pain and agony to myself and my wife. ... Please be merciful and give me an endless sleep as soon as you can so this pain and suffering that I have will be no more."

But Stanworth's death sentence was twice reversed by the high court.

The first time, the court found that three prospective jurors had been improperly dismissed because they said they did not believe in the death penalty. They should have been questioned about whether they could nevertheless return a death verdict, the court said.

After Stanworth's second death sentence was thrown out, he was deemed to be eligible eventually for parole - at that time, life without parole was not an option. He was released from prison in 1990.

"His sentence was life - it should have been life," said O'Connell, the Vallejo police lieutenant. He added, however, "I respect the law and enforce the law as it's given to us."

Mother 'well liked'

Now, Stanworth is being held without bail in Solano County Jail on suspicion of murder.

Stanworth's mother had mobility problems stemming from a fall several months ago, but otherwise seemed to be "in perfect health," said Bensing, her neighbor.

She took pride growing tomatoes and other plants at the mobile-home park, where she sat in her favorite white rocking chair in her driveway and chatted with neighbors, Bensing said.

"She talked to everybody up and down the street," he said. "People would bring her cakes and pies. She was very well liked."